Credit for the invention of photography is attributed variously to Joseph Nicéphore Niépce (1765—1833), Louis Daguerre (1787—1851), and William Henry Fox Talbot (1800—1877). Talbot's discovery of a process using a negative allowed the image to be printed repeatedly, unreversed, on another medium such as paper. It is this process that became the standard for photography until the recent advent of digital photography. Most early use of photography in books required that separately printed photographs be inserted into each volume of an edition by hand, a costly process. By the 1880s, a much cheaper method had come into use: the halftone photomechanical process used a screen to transform the photographic image into dots. Depending on how the dots were reproduced, halftones could be printed by relief or planographic printing methods. When combined with the use of the three primary colors, halftones drove out chromolithography for most color printing by the beginning of the twentieth century.

Scientific uses for photography were seen from the beginning. In anatomy and in botany, the old graphic methods are still used to illustrate general principles, since photography can show only a specific human body or plant specimen.


Lick Observatory, University of California
Transparencies of the Moon, ca. 1896
The New York Public Library

Images of these items illustrate but a few of The New York Public Library's major holdings in science and medicine as well as items from other institutions which were featured in the exhibition Seeing Is Believing,on view from October 23, 1999—February 19, 2000 at the Humanities and Social Sciences Library, and related publication.


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